## good
##
$tmp = 'some string'. $array[$i] . 'some string';


## but, don't work
##
$tmp = 'some string'. &$array[$i] . 'some string';


## also, very not good
##
...
$foo = &$array[$i];
$tmp = 'some string' . $foo . 'some string';
...


## good(simple make array)
##
...
$tmp['foo'][] = &$array[$i];
...